Impact of farmland management on fertilizer reduction in rice production
JILong, XUChunchun, LIFengbo, FANGFuping China National Rice Research Institute, Hangzhou 310006, China 通讯作者:通讯作者:方福平,E-mail:fangfuping@caas.cn 收稿日期:2017-11-1 修回日期:2018-10-11 网络出版日期:2018-12-20 版权声明:2018《资源科学》编辑部《资源科学》编辑部 基金资助:国家重点研发计划项目(2016YFD0200800)国家高技术研究发展计划(863计划)(2014AA10A605) 作者简介: -->作者简介:纪龙,男,湖北丹江口人,博士,助理研究员,主要从事农业经济理论与政策、环境与资源经济等方面研究。E-mail:jilong@caas.cn
关键词:农地经营;化肥减量;广义有序Logit模型;农户;水稻;长江中下游 Abstract The excessive use of fertilizer is a serious issue throughout China and it has resulted in a lot of adverse environmental and economic impacts. Reducing fertilizer input is an important measure to promote the green development of agriculture. Based on household survey data from 29 counties of six provinces in the middle and lower Yangtze River in China, this study has analyzed the impact of land management, including farm size, land concentration, land rent, and tenure security on farmers’ fertilizer input using Generalized Ordered Logit model. The results show that, farm size and land concentration have significant negative effects while land rent has significant positive effect on farmers’ fertilizer input. However, no evidence is found that tenure security can significantly influence farmers’ fertilizer input. Farmers with large farm size are more reasonable than smallholder farmers in terms of fertilizer inputs. It is noted that the effect of farm size on fertilizer reduction decreases with an increase in farm size. That is to say, it does not mean that the larger farm size, the better effect on fertilizer reduction. In the present study, to reduce farmers’ fertilizer input in rice production, the optimal farm size is 0.67 ~ 3.33hm2, and the suboptimal farm size is 3.33 ~ 13.33 hm2 and 13.33 ~ 33.33 hm2. In terms of the extent of influence of these land management factors, farm size has the greatest effect on farmers’ fertilizer input, followed by land concentration and land rent. Therefore, to reduce farmers’ fertilizer input, the government should promote moderate scale operation of farmland and increase the degree of land concentration during the rapid development of land transfer. Furthermore, improving the price mechanism of the land rent and preventing the excessive growth in land rent are also helpful to reduce farmers’ fertilizer input.
4.1.1 户主个体及家庭特征 表2为样本农户的基本统计特征。从表2可以看出,受访农户中户主以男性为主,占95.43%;户主年龄主要集中在45~60岁之间,占61.3%;文化程度以初中和高中(中专、职高)居多,分别占47.12%和32.21%;家庭年收入超过5万元的农户占81.73%,超过8万元的比例占61.30%;农户兼业现象普遍存在,非农收入占比为50%及以上的农户比例达40.14%,纯农户(非农收入占比在10%以下)的比例仅为25%。 Table 2 表2 表2长江中下游六省样本农户的基本统计特征 Table 2Basic characteristics of the samples in six provinces in Yangtze River Basin
个体及家庭特征
户数
百分比/%
农地经营特征
户数
百分比/%
性别
男
397
95.43
水稻种植面积/ hm2
<0.67
58
13.94
女
19
4.57
0.67~3.33
60
14.42
年龄/岁
<30
2
0.48
3.33~13.33
101
24.28
30~45
98
23.56
13.33~33.33
108
25.96
45~60
255
61.30
≥33.33
89
21.39
≥60
61
14.66
受教育程度
小学及以下
61
14.66
土地租金/(元/hm2)
<4 500
112
26.92
初中
196
47.12
4 500~9 000
183
43.99
高中(中专、职高)
134
32.21
9 000~15 000
98
23.56
大专(本科及以上)
25
6.01
≥15 000
23
5.53
家庭年收入/万元
<3
23
5.53
合同年限/年
<3
137
32.93
3~5
53
12.74
3~5
167
40.14
5~8
85
20.43
5~10
30
7.21
≥8
255
61.30
≥10
82
19.71
非农收入占比/%
<10
104
25.00
地块集中程度
分散
157
37.74
10~50
145
34.86
较为集中
170
40.87
≥50
167
40.14
集中
89
21.39
注:地块集中程度的判别依据主要是农户的主观认知。通常认为,以各地块间的距离作为判别依据会更为科学,但如果地块较多,则很难获得准确的距离数据。农户对其经营地块集中程度的主观认知可能是一个理想的次优选择,因为该主观认知是农户生产决策行为的重要影响因素之一。 新窗口打开 4.1.2 农户农地经营特征 从经营规模看,水稻种植面积在3.33hm2及以上的农户占比71.63%,其中不同规模农户的分布较为均衡;土地细碎化问题仍然比较突出,认为地块相对集中的农户比例仅为21.39%;土地租金在(4500~9000)元/hm2的农户比例较大,为43.99%,有5.53%的农户的土地租金超过1.5万元/ hm2;农地流转合同年限较短且规范性较差,73.08%的农户的合同年限在5年及以下,其中合同年限在3年以下的比例为32.93%。 4.1.3 农地经营与农户化肥投入的交叉分析 表3描述了农地经营与农户化肥投入之间的关系。参照张晓恒等的研究并结合实地调查情况[24],本文将农户的土地经营规模划分为五个等级,以0.67hm2、3.33hm2、13.33hm2和33.33hm2为分界点。从经营规模来看,农户化肥投入量与土地经营规模呈明显的负相关关系。随着经营规模扩大,农户化肥投入量(包括化肥总量和氮肥)呈递减趋势。与之相反,化肥投入量与土地租金基本呈正相关,租金越高,农户化肥投入量越大。从合同签约年限来看,3年期限是一个明显的临界点。合同年限在3年以下的农户(包括不签合同的农户,这些农户在进行农地流转时仅达成口头协议而没有形成书面合同),其化肥投入量明显高于其他农户。合同年限在3年及以上的农户,其化肥投入水平基本相当,没有明显差异。农户的化肥投入量与地块集中程度不存在明显的线性关系。总体来看,农户化肥投入水平与土地经营规模、土地租金之间的关系基本符合上述研究假说,而与地块集中程度和地权稳定性之间的关系尚不明确。 Table 3 表3 表3样本区农地经营与农户化肥投入的交叉分析 Table 3Cross analysis of land management and farmers’ fertilizer input in the sample area (kg/hm2)
表5中的估计系数反映了不同因素对农户化肥投入水平的影响方向,但难以准确解释这些因素的影响程度。对此,在上述估计结果的基础上本文进一步分析农地经营对农户化肥投入的边际效应。广义有序Logit模型中,边际效应是指在其他变量保持不变的情况下某自变量的变化对个体选择某一特定类别概率的影响[41]。通过边际效应分析,本文能够了解农地经营变化对农户选择不同化肥投入水平概率的影响。对于非线性模型,有多种方法可用来计算边际效应,其中应用较为广泛的两种边际效应是MEMs(Marginal Effects at the Means)和AMEs(Average Marginal Effects)。前者估算了在其他变量取均值时自变量变化对个体选择不同类别概率的影响,而后者估算了所有样本在其他变量取实际值时自变量变化引起个体选择概率变化的均值,相对而言后者的计算方式更为合理[54]。因此,本文将采用AMEs计算方法来分析农地经营对化肥投入的边际效应,估计结果见表6。 Table 6 表6 表6样本区农地经营对农户化肥投入的边际效应 Table 6Marginal effects of the land management on farmers’ fertilizer input in the sample area
基于上述研究结论得到的政策启示是: (1)继续推进土地适度规模经营。各地应积极推动土地有序流转,扩大经营规模。根据农户经营能力、地区资源禀赋等因素引导农户发展适度规模经营,警惕和避免土地经营规模过大而造成生产经营的粗放管理。同时,在土地经营规模扩大的基础上,各地应通过多种举措促成地块的集中连片,为农户化肥减量投入提供有利条件。 (2)进一步规范和完善土地流转市场,改进和加强对大规模经营农户的支持和补贴。在保障农地转出户合理权益的同时也要为农地转入户减轻成本压力。在土地租金不断走高的背景下,政府应创新农业支持政策,改进对大规模经营农户的补贴方式,为农户的绿色生产行为提供有效激励。 (3)积极培育新型职业农民,减少农户兼业行为。各地应建立更加完善的社会保障体系,让农民安心转让土地经营权,促进土地向少数农户集中。同时,要大力培养新型职业农民,减少兼业农户;提高种粮大户等新型经营主体培训效果,促进农户化肥减量投入。 The authors have declared that no competing interests exist.
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